From 75cba05f491c52fe044f3c966cd0a7d7a20bb9bd Mon Sep 17 00:00:00 2001
From: Huangzj <huangzj@123>
Date: Fri, 5 Feb 2021 14:47:59 +0800
Subject: [PATCH] =?UTF-8?q?feat(Go-Tool)=EF=BC=9A2021/2/5:=20=20=20?=
 =?UTF-8?q?=E6=96=B0=E5=A2=9E=E4=BA=8C=E5=88=86=E6=9F=A5=E6=89=BE=E5=8C=BA?=
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Content-Transfer-Encoding: 8bit

---
 readme.md                        |  2 +
 util/search/BinarySearch.go      | 24 ++++++++++++
 util/search/BinarySearch_test.go | 63 ++++++++++++++++++++++++++++++++
 3 files changed, 89 insertions(+)

diff --git a/readme.md b/readme.md
index bc827ac..3d5fb38 100644
--- a/readme.md
+++ b/readme.md
@@ -68,6 +68,8 @@
 
 2020/12/31：新增项目案例（角色技能树）
 
+2021/2/5:   新增二分查找区间内数值方法
+
 # 修复日志
 2020/11/23：修改项目案例(按照一定规则对一组数据进行排序分组)
 
diff --git a/util/search/BinarySearch.go b/util/search/BinarySearch.go
index 1cd1d49..3c9956b 100644
--- a/util/search/BinarySearch.go
+++ b/util/search/BinarySearch.go
@@ -26,3 +26,27 @@ func BinarySearch(list []int, value int) int {
 
 	return -1
 }
+
+//二分查找在两个数值之间的数据
+func BinarySearchBetween(list []int, value int) int {
+	low := 0
+	high := len(list) - 1
+	var mid int
+
+	for low <= high {
+		//求mid
+		mid = (low + high) >> 1
+		//要算后面一个元素，所以下标要判断是否超过 并且需要考虑超过数组最大值的情况
+		if (mid+1 < len(list) && value > list[mid] && value < list[mid+1]) || value == list[mid] || (mid+1 >= len(list) && value > list[mid]) {
+			return mid
+		}
+		//位移
+		if value < list[mid] {
+			high = mid - 1
+		} else {
+			low = mid + 1
+		}
+	}
+	//未找到元素
+	return -1
+}
diff --git a/util/search/BinarySearch_test.go b/util/search/BinarySearch_test.go
index f4debed..8bf43cb 100644
--- a/util/search/BinarySearch_test.go
+++ b/util/search/BinarySearch_test.go
@@ -40,3 +40,66 @@ func TestBinarySearch(t *testing.T) {
 	position = BinarySearch(oddNumList, -10)
 	fmt.Println(position)
 }
+
+func TestBinarySearchBetween(t *testing.T) {
+
+	evenNumList := []int{1, 2, 3, 5, 6, 7, 9, 10, 22, 111, 333, 431}
+
+	for _, r := range evenNumList {
+		position := BinarySearchBetween(evenNumList, r)
+		fmt.Println(position)
+	}
+
+	position := BinarySearchBetween(evenNumList, 999)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(evenNumList, -10)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(evenNumList, 1)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(evenNumList, 3211)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(evenNumList, 334)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(evenNumList, 110)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(evenNumList, 3222)
+	fmt.Println(position)
+
+	fmt.Println()
+
+	oddNumList := []int{1, 2, 3, 5, 6, 7, 9, 10, 22, 111, 333, 431, 3211}
+	for _, r := range oddNumList {
+		position := BinarySearchBetween(oddNumList, r)
+		fmt.Println(position)
+	}
+
+	fmt.Println("测试between")
+	fmt.Println()
+
+	position = BinarySearchBetween(oddNumList, 999)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(oddNumList, -10)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(oddNumList, 1)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(oddNumList, 3211)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(oddNumList, 334)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(oddNumList, 110)
+	fmt.Println(position)
+
+	position = BinarySearchBetween(oddNumList, 3222)
+	fmt.Println(position)
+}